Given this example, if each line isn't marked off, then most of
the style sheet will become part of the comment, and so will not work:

H1 {color: gray;} /* This CSS comment is several lines
H2 {color: silver;} long, but since it is not wrapped
P {color: white;} in comment markers, the last three
PRE {color: gray;} styles are part of the comment. */

In this example, only the first rule (H1 {color: gray;}) will be
applied to the document. The rest of the rules, as part of the comment, are
ignored by the browser's rendering engine.

Moving on with our example, we see some more CSS information
actually found inside an HTML tag!

Inline Styles

<P STYLE="color: gray;">The most wonderful of all breakfast foods is the waffle-- a ridged and cratered slab of home-cooked, fluffy goodness...
</P>

For cases where you want to simply assign a few styles to one
individual element, without the need for embedded or external style sheets,
you'll employ the HTML attribute STYLE to set an
inline style. The STYLE
attribute is new to HTML, and it can be associated with any HTML tag
whatsoever, except for those tags which are found outside of BODY (HEAD or TITLE, for instance).

The syntax of a STYLE attribute is
fairly ordinary. In fact, it looks very much like the declarations found in
the STYLE container, except here the curly brackets
are replaced by double quotation marks. So <PSTYLE="color:maroon;background:yellow;">
will set the text color to be maroon and the background to be yellow for that paragraph only. No other part of the document will be affected by this declaration.

Summary

In order to facilitate a return to structural HTML, something was needed to permit authors to specify how a document should be displayed. CSS fills that need very nicely, and far better than the various presentational HTML elements ever did (or probably could have done). For the first time in years, there is hope that web pages can become more structural, not less, and at the same time the promise that they can have a more sophisticated look than ever before.

In order to ensure that this transition goes as smoothly as
possible, HTML introduces a number of ways to link HTML and CSS together while
still keeping them distinct. This allows authors to simplify document
appearance management and maximize their effectiveness, thereby making their
jobs a little easier. The further benefits of improving accessibility and
positioning documents for a switch to an XML world make CSS a compelling
technology.

As for user agent support, the LINK
element has been universally supported, as have both the STYLE element and attribute. @import didn't fare so well, though, being ignored
outright by Navigator 4. This is not such a major tragedy, annoying though it
might be, since the LINK element will still let you
bring external style sheets into play.

In order to fully understand how CSS can do all of this, authors
need a firm grasp of how CSS handles document structure, how one writes rules
that behave as expected, and most of all, what the "Cascading" part of the
name really means.